Vacuum cleaner hoses are known which provide one or more electrical conductors connected to an attachment for a vacuum cleaner, such as a motor driven work tool. This arrangement eliminates the necessity of a separate source of current for the work tool and therefore facilitates the operation of the work tool since no extra cables are in the way of the floor maintenance operation. It is thus apparent that the vacuum cleaner hose has a two-fold function, i.e., partly to convey dust laden air from the working tool to the dust container which is housed inside the vacuum cleaner, and partly to conduct electrical energy to the driving motor of the working tool by means of the electrical conductor thereon.
In many cases, the electrical conductor is placed directly on the hose and the hose is then provided with an outer layer covering the conductor. It is also known to place the conductor into a groove arranged in the hose. In the latter case, the conductor is either fixed in the groove or it is permitted to have a certain amount of axial movability in the groove. It will be apparent that in the first case where the conductor is fixed in the groove a rather rigid hose is obtained because during bending of such a hose the conductor is exposed to maximum stretching strain which makes the hose difficult to handle. Furthermore, such an arrangement causes an increased wear of the hose which after some time may result in hose damage or breakage. In the second example, when the conductor is loosely inserted in a groove forming a spiral in the hose structure, the conductor participates during the bending of the hose in the longitudinal direction of the hose wall. This arrangement results in the hose being easier to bend in the handle.
Another known arrangement with respect to electrical connectors and vacuum cleaner hoses is to shape a hose of two loose flexible tubes being an inner and outer tube with the electrical conductor arranged in a space between the tubes so the conductor is essentially parallel to the longitudinal axis of the hose. However, this particular arrangement has a drawback in that upon bending of the hose, the conductor will be exposed to the same stretching strain as if it were rigidly connected to said hose.
It is an object of the present invention to provide a vacuum cleaner hose carrying an electrical conductor which is light weight, easy to bend, and is relatively inexpensive to manufacture. In order to achieve the foregoing objectives the inner and outer vacuum cleaner hose tubes have selected diameters so that an electrical conductor can be positioned therebetween and is able to freely move in the space.
A further object of the present invention is to provide spaced means in the space between the outer and inner vacuum cleaner hose tubes which maintains the shape and orientation of the electrical conductor present in said space.